Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular enzyme activities can be greatly influenced by alterations of pH, and non-physiologic pH may inhibit cell metabolism. The study was undertaken to examine the influence of pH values in preservation solution on ischemic tolerance time of the liver. BDE rat livers were used. Livers were preserved for 20 min or 2 h in warm ischemia after an initial perfusion with Ringer's solution at pH 9.0, 7.4, and 6.0. The values of total adenine nucleotide (TAN) and energy reserve (ER) in the livers were determined at the end of the preservation. After 20 min of warm ischemia, TAN values at pH 9.0 and 7.4 fell to 2.727 +/- 0.255 and 2.410 +/- 0.164 mumol/g, respectively (normal values: 3.414 +/- 0.270 mumol/g) and ER values to 0.786 +/- 0.186 mumol/g at pH 9.0 and to 0.446 +/- 0.095 mumol/g at pH 7.4 (normal values: 2.962 +/- 0.214 mumol/g). A similar trend was also observed after 2 h of warm ischemia. The preservation with a solution at pH 6.0 did not present any difference as compared to that at pH 7.4. Four-hour preservation in cold ischemia with Ringer's solution at pH 9.0 rendered higher values of TAN (2.635 +/- 0.085 mumol/g) and ER (0.336 +/- 0.026 mumol/g) than those in preservation at pH 7.4. No significant difference between TAN and ER values was found when 4-h preservation at pH 7.4 and 6.0 was compared. In another group an intermittent liver perfusion at 1-h interval was performed with chilled Ringer's solution; afterwards GOT, GPT, beta-glucuronidase, and acid phosphatase values in the effluents were evaluated. All of these enzymes showed higher concentration in the effluent with solution at pH 7.4 than that at 9.0. These results suggested that better intracellular energy reserve and organ viability can be maintained by preservation with alkaline solution. Furthermore, ER values seemed to be an excellent indicator of the organ viability during preservation. These were also confirmed by orthotopic hepatic transplantation in pigs. Livers were successfully preserved with alkaline Ringer's solution for up to 12 h. However, without change of pH, livers could not be preserved for more than 4.5 h.
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PMID:[Prolongation of ischemic tolerance time of donor livers by alkaline preservation solutions]. 647 1

Proximal tubular segments (S1, S2 and S3) of the rabbit kidney were incubated in oxygenated Ringer's solution (30 min, pH 7.4, 37 degrees C) containing bovine serum albumin (10 g/l) and [3H]morphine (0.7 microM). The uptake, expressed as tissue water/medium ratio at equilibrium, for S1 was 42.2 +/- 3.95 (mean +/- S.E.), n = 16 tubules from six animals; for S2, 41.6 +/- 4.17, n = 18 tubules from six animals; and for S3, 29.0 +/- 3.83, n = 15 tubules from six animals, a value significantly lower (P less than .05) than in the S1 and S2 segment. High-performance liquid chromatography analysis of the accumulated tritium revealed metabolism of [3H]morphine. Unchanged morphine represented 35.5 +/- 3.4% of the total radioactivity recovered in the extract from S1 segments, 51.1 +/- 7.7% from S2 and 77.3 +/- 1.8 from S3 segments. After treating the tubular extracts with beta-glucuronidase (5 hr, 25 degrees C), all the recovered radioactivity represented unchanged morphine. The main metabolite, thus, was a glucuronide. KCN (10(-2) M), mepiperphenidol (Darstine, 10(-4) M) and quinine (10(-4) M) inhibited [3H]morphine uptake by 55-70%. Surprisingly, there was no decrease in uptake in the presence of N1-methylnicotinamide (10(-3) M). We conclude that the whole proximal tubule is able to accumulate morphine by a specific transport system for organic cations, but that part of this uptake might be due to cellular metabolism and intracellular binding of the drug.
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PMID:Transport and metabolism of [3H]morphine in isolated, nonperfused proximal tubular segments of the rabbit kidney. 714 42